(1) Field of the Invention
The present invention relates to a cylinder injection type engine directly feeding a fuel to a combustion chamber by an injector.
(2) Description of Related Art
As described in patent document 1 (JP-A-2006-132398), there is disclosed a control technique of a dual injection type internal combustion engine which can intend to stabilize a combustion after a cold start of an engine and can reduce an unburned fuel (hereinafter, refer to as HC) and can warm up a catalyst in an early timing, by delaying an opening timing of an intake valve, making a lift amount of the intake valve small, and feeding the fuel by both of an injector injecting the fuel to an intake port and an injector injecting the fuel to an inner side of the cylinder.
Further, as described in patent document 2 (JP-A-2000-8915), there is disclosed a technique of a cylinder injection type internal combustion engine which reduces the HC by controlling an opening timing of an intake valve and a fuel injection timing, forming a flow by an intake air within a combustion chamber by making a lift amount small, and suppressing a fuel attachment to a piston crowned face and a cylinder wall surface at a time of warming up.
Since the warm-up of the catalyst is not finished just after starting at a cold time of the engine, a processing capacity (a purifying capacity) of the catalyst is not sufficient. Accordingly, it is demanded to reduce the HC generated until the warm-up of the catalyst is finished, and activate the catalyst in an early time.
The technique described in the patent document 1 is the technique relating to the dual injection type internal combustion engine mounting both the injector injecting the fuel to the intake port and the injector injecting the fuel into the cylinder therein, and since the opening timing of the intake valve is delayed and a flow rate toward a piston direction is enlarged, a fuel attaching amount to the piston crowned face is large.
Further, in the technique described in the patent document 2, a flow of the intake air is slow in the case that a lift amount of the intake valve is equal to (larger than) the normal one, and it is impossible to sufficiently suppress a fuel attachment to a cylinder bore wall surface. In the case that the lift amount of the intake valve is made small, and the valve opening timing is delayed, the flow of the intake air heading for the piston direction becomes strong, the fuel attachment to the piston crowned face is much, and the generation of the HC is increased.